1. Field of the Invention
The present invention relates to a traffic control system for controlling traffic of vehicles such as cars.
2. Related Background Art
Known as such a kind of traffic control system is one disclosed in Japanese Patent Application Laid-Open No. HEI 7-29091. This traffic control system computes traffic volume data for each intersection according to captured image data obtained by a TV camera disposed above a road near the intersection. Its centralized monitoring center collects and analyzes traffic volume data obtained at a plurality of intersections, so as to set respective on/off times of signals optimal for eliminating traffic jams at the intersections, thereby controlling the signals according to thus set on/off times.
Also known as a traffic monitoring system for monitoring the state of traffic is one disclosed in Japanese Patent Application Laid-Open No. HEI 8-221658, for example. In this traffic monitoring system, an SAR (Synthetic Aperture Radar) is mounted as an imaging radar in an airship, information acquired by the SAR is sent to a ground station, and an information processing unit in the ground station analyzes thus sent information as an image, so as to determine the length of vehicles in congestion and the like, thereby providing thus determined information as traffic information.
However, the traffic control system disclosed in Japanese Patent Application Laid-Open No. HEI 7-29091 carries out image processing for the images captured by TV cameras disposed above roads near intersections, thereby being problematic in that only data within a quite limited area near intersections can be processed. For accurately grasping the state of traffic, TV cameras may further be disposed at not only the intersections but also many other places, so as to monitor images from these TV cameras, thereby getting hold of the state of traffic, which changes depending on time and place. However, there have been restrictions concerning the cost of TV cameras, their cost of installation, how to secure a space for installing TV cameras, and so forth, whereby it has been practically impossible for TV cameras to be installed at places other than intersections, main intersections to be exact, thus imposing a limit on accurately grasping the state of traffic.
On the other hand, the traffic control system disclosed in Japanese Patent Application Laid-Open No. HEI 8-221685 merely provides vehicles and the like with traffic information obtained from information acquired by the SAR mounted in an airship in the sky, and is not configured so as to control traffic according to the information acquired by the SAR.
In view of such circumstances, it is an object of the present invention to provide a traffic control system which can grasp the state of traffic in a wide area and control the traffic according to thus grasped state of traffic.
The traffic control system in accordance with the present invention comprises imaging means, disposed in a flying object, for capturing an image of a predetermined subject area including a road from thereabove and outputting thus captured image data; captured image data transmitting means, disposed in the flying object, for transmitting via a wireless communication line the captured image data outputted from the imaging means; captured image data receiving means for receiving the captured image data transmitted from the captured image data transmitting means; traffic state grasping means for grasping a state of traffic in the subject area according to the captured image data received by the captured image data receiving means; and traffic control means for controlling traffic according to the state of traffic in the subject area grasped by the traffic state grasping means.
In the traffic control system in accordance with the present invention, a flying object is provided with imaging means and captured image data transmitting means, whereas traffic state grasping means captures the state of traffic in the subject area according to the captured image data received by the captured image data receiving means, whereby not only the state of traffic over a wide area can be grasped at once, but also the state of traffic in the subject area can be captured two-dimensionally. As a result, the state of traffic in a wide area can be grasped quite accurately. Also, since a single piece of imaging means can grasp, the state of traffic over a wide area, the traffic monitoring system can lower its cost. Further, since traffic control means controls traffic according to the state of traffic in the subject area grasped by the traffic state grasping means, appropriate traffic control can be carried out in a wide area.
Preferably, the traffic control means controls a parameter of a signal so as to regulate the number of passing vehicles. In the case with such a configuration, the number of vehicles passing the signal is regulated by signal control means according to the state of traffic grasped by the traffic state grasping means, whereby appropriate traffic control for eliminating congested states and the like can be carried out according to the very accurate state of traffic grasped by the traffic state grasping means.
Preferably, the traffic control system further comprises traffic region data extracting means for extracting data of a vehicle traveling region from within the captured image data according to map data, whereas the traffic state grasping means grasps data concerning a traffic volume in the vehicle traveling region according to the data of vehicle traveling region extracted by the traffic region data extracting means. As a consequence, data concerning traffic volumes such as the number of vehicles and vehicle speeds in the vehicle traveling region can be grasped appropriately and easily.
Preferably, the traffic control system further comprises traffic region data extracting means for extracting data of a parking region from within the captured image data according to map data, whereas the traffic state grasping means grasps data concerning vehicles in the parking region according to the data of parking region extracted by the traffic region data extracting means. As a consequence, data concerning parked vehicles such as the number of vehicles parked in the parking region can be grasped appropriately and easily.
Preferably, the imaging means is an imaging radar mounted in the flying object. As a consequence, image data in a very wide area can be obtained.
Preferably, the traffic control system further comprises congestion information providing means for providing a driver with traffic congestion information according to the state of traffic grasped by the traffic state grasping means. As a consequence, the driver can easily see traffic congestion information such as the length of congestion in a highway and the time required for the travel to a destination.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.